Final answer:
The metallic element used for corrosion-resistant coatings inside cans is tin, which provides a protective oxide layer to the underlying steel, commonly referred to as 'tin cans'.
Step-by-step explanation:
The metallic element that is commonly used as a corrosion-resistant coating on the inside of cans used for packaging food, oil, and other substances is tin. The use of tin as a coating material for steel is a common technique to prevent the corrosion of iron by forming a protective layer. This is often referred to colloquially when people speak of "tin cans", which are actually made of steel that is coated with a thin layer of tin. Tin forms protective oxide coatings that hinder the access of oxygen and water to the underlying steel, thus preventing corrosion. While zinc is also used in protective coatings, such as in the galvanization process, the specific application to food packaging cans is more commonly associated with tin coatings.